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Distinct oxygen isotope compositions of the Earth and Moon


The virtually identical oxygen isotope compositions of the Earth and Moon revealed by Apollo return samples have been a challenging constraint for lunar formation models. For a giant impact scenario to explain this observation, either the precursors to the Earth and Moon had identical oxygen isotope values or extensive homogenization of the two bodies occurred following the impact event. Here we present high-precision oxygen isotope analyses of a range of lunar lithologies and show that the Earth and Moon in fact have distinctly different oxygen isotope compositions. Oxygen isotope values of lunar samples correlate with lithology, and we propose that the differences can be explained by mixing between isotopically light vapour, generated by the impact, and the outermost portion of the early lunar magma ocean. Our data suggest that samples derived from the deep lunar mantle, which are isotopically heavy compared to Earth, have isotopic compositions that are most representative of the proto-lunar impactor ‘Theia’. Our findings imply that the distinct oxygen isotope compositions of Theia and Earth were not completely homogenized by the Moon-forming impact, thus providing quantitative evidence that Theia could have formed farther from the Sun than did Earth.

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Fig. 1: Plot of Δ′17O versus δ′18O for lunar and terrestrial samples.
Fig. 2: Box-and-whisker plot showing the Δ′17O values for the different lunar lithologies and Earth.
Fig. 3: Plot of Δ′17O versus TiO2 content for high- and low-Ti lunar mare basalts, volcanic glasses and associated mineral separates.
Fig. 4: Plot of Δ′17O versus Δ′18OPl–Px/Ol and θ values for mineral pairs of terrestrial and lunar samples.

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Data availability

The authors declare that the necessary data supporting the findings of this study are available within the paper and its supplementary information files. All other datasets generated during and/or analysed during the current study are available from the corresponding author on reasonable request.


  1. Hartmann, W. K. & Davis, D. R. Satellite-sized planetesimals and lunar origin. Icarus 24, 504–515 (1975).

    Google Scholar 

  2. Cameron, A. G. W. & Ward, W. R. The origin of the Moon. Abstr. Lunar Planet. Sci. Conf. 7, 120 (1976).

    Google Scholar 

  3. Cameron, A. G. W. & Benz, W. The origin of the moon and the single impact hypothesis IV. Icarus 92, 204–216 (1991).

    Google Scholar 

  4. Cameron, A. G. W. The origin of the Moon and the single impact hypothesis V. Icarus 126, 126–137 (1997).

    Google Scholar 

  5. Canup, R. M. & Asphaug, E. Origin of the Moon in a giant impact near the end of the Earth’s formation. Nature 412, 708–712 (2001).

    Google Scholar 

  6. Benz, W., Slattery, W. L. & Cameron, A. G. W. The origin of the moon and the single-impact hypothesis I. Icarus 66, 515–535 (1986).

    Google Scholar 

  7. Benz, W., Slattery, W. L. & Cameron, A. G. W. The origin of the moon and the single-impact hypothesis, II. Icarus 71, 30–45 (1987).

    Google Scholar 

  8. Benz, W., Cameron, A. G. W. & Melosh, H. J. The origin of the moon and the single-impact hypothesis III. Icarus 81, 113–131 (1989).

    Google Scholar 

  9. Melosh, H. J. & Kipp, M. E. Giant impact theory of the Moon’s origin: first 3-D hydrocode results. Abstr. Lunar Planet. Sci. Conf. 20, 685 (1989).

    Google Scholar 

  10. Dauphas, N. et al. Magma redox and structural controls on iron isotope variations in Earth’s mantle and crust. Earth Planet. Sci. Lett. 398, 127–140 (2014).

    Google Scholar 

  11. Melosh, H. J. New approaches to the Moon’s isotopic crisis. Philos. Trans. R. Soc. A 372, 20130168 (2014).

    Google Scholar 

  12. Stevenson, D. J. & Halliday, A. N. The origin of the Moon. Philos. Trans. R. Soc. A 372, 2014028 (2014).

    Google Scholar 

  13. Hauri, E. H., Saal, A. E., Rutherford, M. J. & Van Orman, J. A. Water in the Moon’s interior: truth and consequences. Earth Planet. Sci. Lett. 409, 252–264 (2015).

    Google Scholar 

  14. Wiechert, U. et al. Oxygen isotopes and the Moon-forming giant impact. Science 294, 345–348 (2001).

    Google Scholar 

  15. Spicuzza, M. J., Day, J. M. D., Taylor, L. A. & Valley, J. W. Oxygen isotope constraints on the origin and differentiation of the Moon. Earth Planet. Sci. Lett. 253, 254–265 (2007).

    Google Scholar 

  16. Hallis, L. J. et al. The oxygen isotope composition, petrology and geochemistry of mare basalts: evidence for large-scale compositional variation in the lunar mantle. Geochim. Cosmochim. Acta 74, 6885–6899 (2010).

    Google Scholar 

  17. Young, E. D. et al. Oxygen isotopic evidence for vigorous mixing during the Moon-forming giant impact. Science 351, 493–496 (2016).

    Google Scholar 

  18. Mastrobuono-Battisti, A., Perets, H. B. & Raymond, S. N. A primordial origin for the compositional similarity between the Earth and the Moon. Nature 520, 212–215 (2015).

    Google Scholar 

  19. Pahlevan, K. & Stevenson, D. J. Equilibration in the aftermath of the lunar-forming giant impact. Earth Planet. Sci. Lett. 262, 438–449 (2007).

    Google Scholar 

  20. Lock, S. J. et al. The origin of the Moon within a terrestrial synestia. J. Geophys. Res. Planets 123, 910–951 (2018).

    Google Scholar 

  21. Wang, K. & Jacobsen, S. B. Potassium isotopic evidence for a high-energy giant impact origin of the Moon. Nature 538, 487–490 (2016).

    Google Scholar 

  22. Canup, R. M. Forming a Moon with an earth-like composition via a giant impact. Science 338, 1052–1055 (2012).

    Google Scholar 

  23. Ćuk, M. & Stewart, S. T. Making the Moon from a fast-spinning Earth: a giant impact followed by resonant despinning. Science 338, 1047–1052 (2012).

    Google Scholar 

  24. Reufer, A., Meier, M. M. M., Benz, W. & Wieler, R. A hit-and-run giant impact scenario. Icarus 221, 296–299 (2012).

    Google Scholar 

  25. Herwartz, D., Pack, A., Friedrichs, B. & Bischoff, A. Identification of the giant impactor Theia in lunar rocks. Science 344, 1146–1150 (2014).

    Google Scholar 

  26. Greenwood, R. C. et al. Oxygen isotopic evidence for accretion of Earth’s water before a high-energy Moon-forming giant impact. Sci. Adv. 4, eaao5928 (2018).

    Google Scholar 

  27. Sharp, Z. D. A laser-based microanalytical method for the in-situ determination of oxygen isotope ratios of silicates and oxides. Geochim. Cosmochim. Acta 54, 1353–1357 (1990).

    Google Scholar 

  28. Shearer, C. K. & Papike, J. J. Basaltic magmatism on the Moon: a perspective from volcanic picritic glass beads. Geochim. Cosmochim. Acta 57, 4785–4812 (1993).

    Google Scholar 

  29. Shearer, C. K., Papike, J. J. & Layne, G. D. Deciphering basaltic magmatism on the Moon from the compositional variations in the Apollo 15 very low-Ti picritic magmas. Geochim. Cosmochim. Acta 60, 509–528 (1996).

    Google Scholar 

  30. Delano, J. W. Pristine lunar glasses: criteria, data, and implications. J. Geophys. Res. Solid Earth 91, 201–213 (1986).

    Google Scholar 

  31. Canup, R. M. Dynamics of lunar formation. Annu. Rev. Astron. Astrophys. 42, 441–475 (2004).

    Google Scholar 

  32. Chakraborty, S., Yanchulova, P. & Thiemens, M. H. Mass-independent oxygen isotopic partitioning during gas-phase SiO2 formation. Science 342, 463–466 (2013).

    Google Scholar 

  33. Spera, F. J. Lunar magma transport phenomena. Geochim. Cosmochim. Acta 56, 2253–2265 (1992).

    Google Scholar 

  34. Taylor, S. R. & Jakes, P. The geochemical evolution of the moon. In Proc. 5th Lunar Science Conference 1287–1305 (Pergamon, 1974).

  35. Elardo, S. M., Draper, D. S. & Shearer, C. K. Lunar magma ocean crystallization revisited: bulk composition, early cumulate mineralogy, and the source regions of the highlands Mg-suite. Geochim. Cosmochim. Acta 75, 3024–3045 (2011).

    Google Scholar 

  36. Shearer, C. K. et al. Thermal and magmatic evolution of the Moon. Rev. Mineral. Geochem. 60, 365–518 (2006).

    Google Scholar 

  37. Ringwood, A. E. & Kesson, S. E. A dynamic model for mare basalt petrogenesis. In Proc. 7th Lunar and Planetary Science Conference 1697–1722 (Pergamon, 1976).

  38. Kesson, S. E. & Ringwood, A. E. Mare basalt petrogenesis in a dynamic moon. Earth Planet. Sci. Lett. 30, 155–163 (1976).

    Google Scholar 

  39. Hess, P. C. & Parmentier, E. M. A model for the thermal and chemical evolution of the Moon’s interior: implications for the onset of mare volcanism. Earth Planet. Sci. Lett. 134, 501–514 (1995).

    Google Scholar 

  40. Zhong, S., Parmentier, E. M. & Zuber, M. T. A dynamic origin for the global asymmetry of lunar mare basalts. Earth Planet. Sci. Lett. 177, 131–140 (2000).

    Google Scholar 

  41. Cao, X. et al. Triple oxygen isotope constraints on the origin of ocean island basalts. Acta Geochim. 38, 327–334 (2019).

  42. Pack, A. & Herwartz, D. The triple oxygen isotope composition of the Earth mantle and understanding variations in terrestrial rocks and minerals. Earth Planet. Sci. Lett. 390, 138–145 (2014).

    Google Scholar 

  43. Meyer, C. Lunar Sample Compendium (NASA/ARES, 2012);

  44. Wostbrock, J. A. G., Cano, E. J. & Sharp, Z. D. An internally consistent triple oxygen isotope calibration of standards for silicates, carbonates and air relative to VSMOW2 and SLAP2. Chem. Geol. 533, 119432 (2020).

    Google Scholar 

  45. Pack, A. et al. The oxygen isotope composition of San Carlos olivine on the VSMOW2–SLAP2 scale. Rapid Commun. Mass Spectrom. 30, 1495–1504 (2016).

    Google Scholar 

  46. Miller, M. F. Isotopic fractionation and the quantification of 17O anomalies in the oxygen three-isotope system: an appraisal and geochemical significance. Geochim. Cosmochim. Acta 66, 1881–1889 (2002).

    Google Scholar 

  47. Young, E. D., Galy, A. & Nagahara, H. Kinetic and equilibrium mass-dependent isotope fractionation laws in nature and their geochemical and cosmochemical significance. Geochim. Cosmochim. Acta 66, 1095–1104 (2002).

    Google Scholar 

  48. Thiemens, M. H. Mass-independent isotope effects in planetary atmospheres and the early solar system. Science 283, 341–345 (1999).

    Google Scholar 

  49. Cao, X. & Liu, Y. Equilibrium mass-dependent fractionation relationships for triple oxygen isotopes. Geochim. Cosmochim. Acta 75, 7435–7445 (2011).

    Google Scholar 

  50. Starkey, N. A. et al. Triple oxygen isotopic composition of the high-3He/4He mantle. Geochim. Cosmochim. Acta 176, 227–238 (2016).

    Google Scholar 

  51. Sharp, Z. D., Wostbrock, J. A. G. & Pack, A. Mass-dependent triple oxygen isotope variations in terrestrial materials. Geochem. Perspect. Lett. 7, 27–31 (2018).

    Google Scholar 

  52. Chiba, H., Chacko, T., Clayton, R. N. & Goldsmith, J. R. Oxygen isotope fractionations involving diopside, forsterite, magnetite, and calcite: application to geothermometry. Geochim. Cosmochim. Acta 53, 2985–2995 (1989).

    Google Scholar 

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We are grateful to NASA and CAPTEM for approving our requests for Apollo samples used in this study. We thank F. Trusdell, M. Perfit, V. S. Kamenetsky, L. S. Crumpler, K. A. Smart, S. Tappe, S. C. Kruckenberg, B. Oller, G. Wörner, L. D. Ashwal and L. E. Borg for the collection and/or donation of sample material. Thank you to S. Locke for sharing his thoughts on post-giant impact dynamics. Thank you to S. Chakraborty and M. H. Thiemens for sharing additional insight regarding their work on mass-independent oxygen isotope fractionation in gas-phase SiO2 formation. We acknowledge support from NSF award 1903852.

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Analyses were made by E.J.C., who also wrote the initial manuscript. All authors contributed ideas, helped construct the project and contributed additions and edits to the initial manuscript.

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Correspondence to Erick J. Cano.

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Extended data

Extended Data Fig. 1 Plot of the change in the Δ′17O value (ΔΔ′17O) of the lunar vapour as a function of the amount lost during early deposition and incorporation into the bulk Moon (F).

If 60% of the vapour is removed into the mantle (F=0.4), the remaining vapour will have a Δ′17O value that is 0.75‰ lighter than the initial vapour (bulk Moon value). In order to change the outer 50 km of the ‘crust’ by 0.05‰, ~4×1023 g of vapour would have to be remixed into the outer crust. The effect on the δ18O value would be minimal.

Extended Data Fig. 2 Plot of δ′18O values of mineral separates from selected lunar samples.

Mineral separate data from the lunar crust samples are measured values and include plagioclase, pyroxene and/or olivine separates from samples 60016, 62237, 77215, and 78238. Mineral separate data for low-Ti Basalts (samples 12018, 12063, 15016, and 15426) are calculated from the whole-rock δ′18O measurements using simple mass-balance equations, modal mineral percentages, and expected isotope fractionations. The ‘theoretical’ mineral values for the VLT glass are calculated from modes estimated from the CIPW norm for this sample. Calculated δ18O mineral separate data, either from CIPW norm or measured modes agree to within <0.1‰. Mineral modes and bulk composition data used to calculate the CIPW norm values are from the Lunar Sample Compendium43. The isotope fractionations used in the mass balance equations are Δ′18OPl-Ol = 0.774, Δ′18OPl-Px = 0.35, Δ′18OPx-Ol = 0.424 (from Chiba et al.52) and assume isotopic equilibrium between mineral phases at 1200 °C.

Extended Data Fig. 3 Calculated Δ′17O values for Theia and Proto-Earth for varying degrees of mixing and initial proto-planet masses.

The plot illustrates the calculated Δ′17O values for Theia and Proto-Earth given varying initial Theia masses (indicated by different line styles) and the percentage of the Moon that is composed of material from Theia. For example, if Theia was initially 0.1 ME and 70% of the Moon is material from Theia, Theia’s initial Δ′17O value was about −0.028‰ and Proto-Earth’s was about −0.062‰. This assumes that the current values of the Moon and Earth are −0.038‰ and −0.060‰ respectively and the summed masses of Theia and Proto-Earth are equivalent to the total mass of the present Earth-Moon system. Increased mixing between Theia and Proto-Earth produce smaller amounts of Theia in the Moon.

Extended Data Fig. 4 Plot of Plot of Δ′17O versus δ′18O for the VLT green glass (15426), high-Ti orange/black glass (74220), and MORB glass (ALV2746-12).

The VLT green glass is represented by the green squares and high-Ti orange/black glass is represented by the yellow diamonds. The MORB glass values are black circles. The coloured in shapes highlight the range in oxygen isotope values for their corresponding data set. This illustrates how large the range seen in the VLT green glass is compared to that seen in homogeneous glass samples measured with identical methods. The green glass has a range over three times that of the high-Ti orange/black glass and the MORB sample, demonstrating that the isotopic heterogeneity in the green glass beads is not a product of the sample analysis and is real variation.

Extended Data Fig. 5 Plot of Δ′17O values for different fractions of very low-Ti green glass (left) with histogram (right).

Various fractions of VLT green glass (sample 15426) were separated by glass bead appearance and measured. Mixed fractions of the green glass containing a random assortment of glass beads ranged from −0.066‰ to −0.037‰, a spread far greater than what can be attributed to analytical error on measurements of a homogeneous sample. When separated by visual appearance, samples ranged from −0.057‰ to −0.025‰ with the dark rimmed fraction having the heaviest measured Δ′17O value in this study. Histogram bins are 0.005‰ wide and include both mixed and separated fractions combined to illustrate the frequency distribution of the measured values.

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Cano, E.J., Sharp, Z.D. & Shearer, C.K. Distinct oxygen isotope compositions of the Earth and Moon. Nat. Geosci. 13, 270–274 (2020).

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